1. Field of the Invention
This invention relates to the field of electronic music instruments, and more specifically, to the keyboards of electronic music instruments.
2. Background Art
The evolution of the electronic keyboard has empowered musicians by eliminating the need for pianists and organists to have bulky, substantially immovable pianos or organs available for practice and performance. Electronic keyboards are small, relatively lightweight, inexpensive, and, in the case of advanced synthesizers, able to simulate the sound of any existing instrument (or any sound source, for that matter). They are easy to transport, easy to set up, and available for impromptu practice or performance in any location. Unfortunately, in eliminating the disadvantages of pianos and organs, electronic keyboards have also eliminated the “feel” of playing a piano or organ. Many musicians prefer the feel of a piano keyboard to that of an electronic keyboard. Further, because the action is different, performance techniques may also vary with respect to playing on a piano keyboard and an electronic keyboard.
The feel of a piano or organ comes from the mechanical action of converting the depression of a key into the striking of a string in a piano or the actuation of an air valve in a pipe organ. The tactile feedback a musician receives from the keyboard action of a piano or organ aids in the musician's control over the qualities of the note played (e.g., the volume of the note and the intensity of the attack). When the musician is playing on an unfamiliar type or brand of piano, the playing may feel “off” because the tactile feedback is not consistent with the musician's learned expectations. The resulting audio qualities of the performance may differ from expectations as well (notes may be too hard or soft sounding because the attack is too strong or weak, and the musician's control of the volume may be diminished). The discomfort and lack of control are even greater when the musician switches to an electronic keyboard in which the familiar mechanical action of a piano or organ keyboard is absent.
A pipe organ generates sounds by channeling pressurized air through one or more selected pipes. The dimensions of the pipe determine the pitch (sound frequency) of the note played, and the air pressure determines the volume. On an organ keyboard, each key actuates an air valve that releases pressurized air into one of the pipes. The amount of key depression determines the amount of air released, and hence the volume of the note played. The keyboard action of the pipe organ is a function of the valve mechanics and the force of the released air on the valve. An electric organ, in contrast, has a key action that is substantially linear in nature, having a constantly increasing resistance force similar to compressing a spring.
In a piano, the properties (length and tension) of a string determine its specific resonance, and therefore the note that may be played by striking the string. Each key of the piano keyboard is the end of a lever set on a fulcrum, the opposing side of which is weighed down by a hammer element. Depression of the key causes the lever to push the hammer toward a particular string. A certain momentum threshold is needed for the hammer to strike the string. Greater momentum will result in a louder note. In addition to swinging the hammer, each key also controls a damper. When the key is held down, the damper is held away from the string. Whereas, when the key is released, the string is damped, causing the string oscillations to diminish more quickly. The mechanics of the damper and the hammer thus contribute to the action or feel of the piano keyboard.
As may be expected, different types of pianos have different mechanics with different keyboard action. For example, the mechanics of a grand piano differ from those of an upright piano. Also, pianos from different makers may also have differences in keyboard action due to differences in hammer mass, lever ratio, and/or damper tension. A musician will feel the most comfortable playing a piano with a familiar keyboard action.
In contrast to pianos and organs, most electronic keyboards and synthesizers have very little action at all. There is no need for a complicated hammer/lever apparatus because the sound is electronically generated. Typically, the keys of an electronic keyboard are hinged on one end, with a spring underneath to return the key to its rest position. The resistance is relatively constant. An electrical contact is sufficient to initiate a sound, and the sound continues to play as long as that contact is maintained (i.e., by holding the key down. The velocity of the key may be detected to provide an initial note volume, but the action of the keyboard does not change with velocity.
Some electronic keyboards attempt to mimic the mechanical characteristics of an acoustic piano, for example, by including hammer-like elements that strike a backing of foam rubber. This mechanical mimicry is an improvement over keyboards with no real action. However, this keyboard action is unlikely to match that of a musician's favorite type and brand of piano. Also, the additional mechanical elements increase the size and weight of the electronic keyboard. Therefore, there is a need for an electronic keyboard that provides the keyboard action of a musician's favorite piano without the added bulk of mechanical elements.